The long-term objective of the proposed grant is to develop an integrated multimodal intravascular imaging system that combines ultra high-resolution intravascular optical coherence tomography (OCT), and intravascular ultrasound (IVUS). This combined multimodal vascular imaging system will permit cross- sectional visualization of vascular arteries with high spatial resolution, broad imaging depth, and high sensitivity not possible with any of these technologies alone. The specific aims of the proposal are to design, development, and optimize an integrated intravascular OCT/US system, and to test and demonstrate in vivo intravascular imaging in animal model and pilot human subject studies. OCT and IVUS provide complementary information for vascular imaging applications. First, OCT &IVUS provide details of the imaged tissue at two different length scales. IVUS resolution is in the order of 50 microns to 200 microns, while OCT images provide details at a much higher resolution in the order of 5 microns to 20 microns. Therefore, IVUS can image a much larger area to choose a suspect lesion or a region in the blood vessel lumen wall, while OCT can be used to see details in the suspect area. Second, OCT has a limited imaging depth of 2 mm, while IVUS can image depth >5mm inside the tissue. Third, the imaging contrasts for IVUS and OCT are different. Recent clinical studies that combines OCT/IVUS data analysis shows that neither modality alone is sufficient for detecting thin-cap fibroatheroma (TCFA) (Sawada et al. European Heart Journal 29:1136-1146). Their results indicate that combined use of OCT and IVUS offers a promising approach for evaluating TCFA. The complementary nature of OCT/IVUS may enable early detection and classification of plaques, identification of stent struts and stent mal-opposition, characterization of vessel dimension and detection of post stent thrombosis. The proposed research requires an interdisciplinary team of scientists, engineers, and clinicians. We have assembled such a team that involves the collaboration of four investigators from three institutions: Optical coherence tomography imaging group (Dr. Chen from Beckman Laser Institute at UCI), Ultrasound imaging group (Dr. Zhou and Shung from the NIH Transducer Resource Center at USC), and Intravascular cardiology group (Dr. Narula from the Dept. of Cardiology at UCI). Each principal investigator has expertise in the key areas required for the success of this project. In preliminary studies conducted at the UCI Beckman Laser Institute and the USC NIH Transducer Resource Center, we have shown that it is possible to combine OCT and IVUS in a single probe. The integrated probe has the advantage of high resolution and broad imaging depth. The proposed research is to extend this finding and to develop and translate this technology from bench top to clinical applications. PUBLIC HEALTH RELEVANCE: Despite significant advances in medicine, cardiovascular diseases remain the number one killer in America. We propose to develop an integrated multimodal intravascular imaging system that combines ultra high-resolution intravascular optical coherence tomography (OCT) with intravascular ultrasound (IVUS). The integrated imaging system will permit cross-sectional visualization of vascular arteries with high spatial resolution, broad imaging depth, and high sensitivity not possible with any of these technologies alone. The proposed research is expected to have significant impact in the earlier detection, prevention, and treatment of cardiovascular diseases.